Predictive biomarkers of response for immune checkpoint inhibitors in non–small-cell lung cancer

Immune checkpoint blockade has been a pivotal development in the management of advanced non–small-cell lung cancer (NSCLC). Although durable antitumour activity and improved survival have been observed in a subset of patients, there is a need for additional predictive biomarkers to improve patient selection and avoid toxicity in potential non-responders. This review will address the use and limitations of tumour programmed death-ligand 1 expression as a predictive biomarker and review emerging biomarker strategies specifically related to NSCLC including genetic alterations (tumour mutation burden, loss and gain activated mutations), tumour-related factors (tumour microenvironment) and factors related to the host immune system. Novel approaches in biomarker detection such as peripheral blood monitoring will also be reviewed. •At present, tumour PD-L1 expression is the only approved biomarker, albeit imperfect, used in clinical practice for PD-(L)1 blockade in NSCLC.•Tumour Mutational Burden may enter clinical practice as a biomarker to select patients who are potential candidates for dual immune blockade.•Several biomarker strategies specifically related to NSCLC are under investigation.•Tumour-related factors such as genetic alterations and tumour microenvironment play a crucial role and are relevant for a prediction role.•Factors related to the host immune system (peripheral blood biomarkers etc.) and their combination with other biomarkers will be the next future.